In an imaging system such as a camera, a solid-state imaging device is placed at a predicted image plane of an imaging lens. The imaging lens forms an image of an object on the imaging region (image plane) of the solid-state imaging device. The solid-state imaging device generates an image signal according to the object image. At this time, if the amounts of received light of pixels in the periphery attenuate relative to pixels near the center in the imaging region, there may occur shading where pixel signals in the periphery of the imaging region attenuate in luminance (signal level) relative to pixel signals in the vicinity of the center of the imaging region, in the image signal generated by the solid-state imaging device.